Bump opencv-python from 4.5.5.64 to 4.8.1.78 in /requirements/gpu

Bumps [opencv-python](https://github.com/opencv/opencv-python) from 4.5.5.64 to 4.8.1.78.
- [Release notes](https://github.com/opencv/opencv-python/releases)
- [Commits](https://github.com/opencv/opencv-python/commits)

---
updated-dependencies:
- dependency-name: opencv-python
  dependency-version: 4.8.1.78
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements/gpu/requirements.txt

@@ -5,7 +5,7 @@ moviepy
 GPUtil
 openai
 gradio
-opencv-python==4.5.5.64
+opencv-python==4.8.1.78
 imgaug==0.4.0
 triton==3.3
 use-triton-in-paddle